Making a two-phase liquid/liquid or gas system in microfluidics

Abstract

The invention relates to a microfluidic device for making a liquid / liquid or gas biphasic system using a first liquid or a gas and a second liquid, non-miscible with each other, the device having a first hydrophobic surface for the second liquid, the first liquid forming a layer (6) on said first hydrophobic surface. The device comprises means for introducing a drop (7) of the second liquid into the layer of first liquid or gas and in contact with said first hydrophobic surface, and means for displacing the drop on said first hydrophobic surface along a determined path, the device having on the path of the drop, at least one wetting defect causing, upon passing of the drop over this defect, failure of the triple line of contact of the drop on the first hydrophobic surface and inclusion of first liquid (8) or gas into the drop.The invention also relates to the associated method.

Description

TECHNICAL FIELD[0001]The invention relates to the making of a liquid / liquid or gas biphasic system in microfluidics.[0002]With such a device liquid lenses with variable focal length may notably be made.STATE OF THE PRIOR ART[0003]Presently, liquid lenses are made by directly injecting oil in water. It seems that there is no microfluidic method for making such a type of inclusion. An explanation of the operation of a liquid lens with a variable focal length is given in the document, <<Variable focal lens controlled by an external voltage: An application of electro-wetting >> of B. BERGE AND J. PESEUX, Eur. Phys. J. E3, 159-163 (2000). However, this document discloses a macroscopic embodiment.[0004]Lenses with variable focal length made in microtechnologies generally use the deformation of solid or liquid membranes by increase or decrease in pressure. On the subject of this technique, reference may be made to the following documents:[0005]<<Tunable microdoublet lens ...

AI Technical Summary

Benefits of technology

[0011]According to a first embodiment, the means for displacing the drop of the second liquid are electrical activation means providing an electro-wetting effect. The electrical activation means may comprise a succession of electrodes comprised in or on a support having a dielectric layer, a surface of which forms the first hydrophobic surface, the succession of electrodes being positioned along said determined path. The device may comprise a second hydrophobic surface positioned facing the first hydrophobic surface so as to form a closed or confined system for the first liquid or gas layer. The electric activation means may comprise a counter-electrode comprised...

Problems solved by technology

This may be a wetting defect of the first hydrophobic surface.

The wetting defect may be a topological defect present on the first hydrophobic surface, for example a protrusion, a hole or a rough area, causing failure of the triple line of the drop of the second liquid, thereby creating an inclusion of the first liquid in said drop of the second liquid.

This may be a wetting defect of the first hydrophobic surface.

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